A wild Shark Face Maiden Flight

[Edward Po]

Hi All Shark Face Lovers

I maiden my Shark Face model last Sunday at my club's flying site. The flight was crazy and wild! It kept on turning to the left and went almost straight upward like a rocket immediately!

Even when applying full right trim (See attached photo), I could not tamed it. In the end it went down without much damaged. My question are as follows :-

1) Should I add Right Thrust to the motor?
2) Reduce the propeller size from 7" x 5" to 6" x 5"
3) Change 3S to 2S battery

The motor on my Shark Face is Turnigy Aerodrive v2 2822/14 1450kV, Battery is 3S 1100mah. There was no visual warped on the airframe. CG was as per construction plan. Guidance by Futaba radio.

Any help or suggestion will be deeply appreciated

[Barry]

Hi Edward, I don't think it is necessary to change the battery size. Try using a 7x4 or a 6x4 prop. Also, don't forget there is no need to use full throttle all the time. Either throttle back on the stick, or reduce the max travel on the transmitter programming. You could add a little right thrust, but I don't think it is essential if you reduce the power. Good luck, the Sharkface is a very lively model !

[Tobe]

Check glide, if straight and nice with center rudder and elevator it's a matter to get the right trust and / or too much power if the down trust is by the drawing. If it's balloning in the glide check CG.
The Sharkface if done electric have a tendency to be tail heavy....the nose should be slightly longer to keep at least the propeller disc in the original position.
A single channel should per se fly with a center rudder on power to assure turns in both directions due of top and bottom rudder...
This kind of models should be trimmed as you trim a free flight!

[bluejets]

Those wings look REAL short.
Did you run out of materials...???

Could be the angle of the photo but the one below looks more in proportion.

[Edward Po]

Hi Tobe and Barry:

Thank you both for your suggestion. I must admit I was flying at full throttle! I will try again this weekend.

[Edward Po]

Those wings look REAL short.
Did you run out of materials...???

Could be the angle of the photo but the one below looks more in proportion.

004.jpg

My Shark Face was built stock according to the plan.

[bluejets]

Can only be a build error or the pilot then......

[Phil_G]

Hi Edward
The Sharkface is a 'hot' model and it does take a while to get used to it!
Yours sounds overpowered, 50 watts is ample - a Cox Babe-Bee was about 45 watts.
Mine all have much smaller motors on 2S, but then they are rudder-only with on/off throttle.
7" is a large prop - a third of the wingspan - and the prop-disc is very close to
the wing, so going down to 6" or 5" will help.
Dont give up, the Sharkie is a great flyer and a very popular choice here!
Cheers
Phil

[Edward Po]

Hi Edward
The Sharkface is a 'hot' model and it does take a while to get used to it!
Yours sounds overpowered, 50 watts is ample - a Cox Babe-Bee was about 45 watts.
Mine all have much smaller motors on 2S, but then they are rudder-only with on/off throttle.
7" is a large prop - a third of the wingspan - and the prop-disc is very close to
the wing, so going down to 6" or 5" will help.
Dont give up, the Sharkie is a great flyer and a very popular choice here!
Cheers
Phil

sharkfest_2012lores.JPG

Hi Phil:

Thank you for your encouragement.
I won't give up and I know that I may be overpowering my Shark. Before my maiden flight, I was actually staring at the 7" propeller which like to you mentioned is one third the wingspan of the model wondering whether it was a good choice, In the end I decided to take the risk hoping that my long flying experience can overcome it.

Anyway, I will be visiting my local hobby shop to source for a smaller propeller to try again this weekend.

On a side note, thanks to all the feedback and advices, I now understand why it was not suitable for Single Channel flying for beginner! Thus I have started the Tomboy Senior build.

[Pchristy]

For what its worth, a Sharkface was my first consistently successful r/c model, back around 1965! Mine flew with a Cox .049, and a rubber driven escapement for control. I still have one in that configuration!

It could be tricky to get away on a calm day, as it needed a javelin-like launch. A stiff breeze made life much easier!

My first one flew straight off the board, with little interference from me! Just as well, as I had virtually no experience!

It only got interesting when you started applying the rudder (no elevators!), as it was very responsive. I learned a lot from that model, and it always brings a smile to my face.

As others have hinted, yours sounds somewhat over-powered and probably tail heavy. Check the CofG carefully! Also, if a smaller prop doesn't help, try fitting it backwards to reduce the thrust.

Best of Luck!

--
Pete